The hyperadrenergic syndrome that occurs in tetanus is characterised by hypertension, tachycardia, and increased systemic arteriolar resistance. A 74 year old man with tetanus was found to have very high catecholamine concentrations--as high as those in phaeochromocytoma--and the fluctuations in blood pressure and heart rate were measured to see whether they paralleled changes in the catecholamine values. A labetalol infusion of 0.25-1 mg/min gradually stabilised the cardiovascular disturbances and the patient recovered.